Spatial contrast sensitivity was used to assess losses or changes in overall visual resolution in patients having a variety of toxic, inflammatory, degenerative, or congenital retinal and neuro-ophthalmological disorders of the visual system. A criterion-free forced-choice psychophysical procedure was used, since this method was previously shown to minimize false positive or false negative diagnoses at initial test and to minimize spurious changes in sensitivity with repeated testing. Contrast sensitivity testing, while requiring more patient testing time, continued to be superior to conventional acuity measurements for the detection of early losses and for monitoring changes in visual resolution in patients undergoing treatment. Age-referenced normative data make it possible to distinguish contrast sensitivity loss due to ocular disorder from that expected on the basis of normal aging. A retinal image stabilization system was used in conjunction with the spatial contrast sensitivity test system to carry our preliminary research on normal subjects using artificial scotomata and complex spatial luminance profiles to examine interactions among fixational errors, eye movements, and visual field defects. This system is currently being modified to permit focal electroretinography and high resolution microperimetry in small, localized regions of the retinas in Eye Clinic patients.